In the related art, in a case in which a multi-pin LSI package, which is used in MPU or a gate array, is mounted on a printed wiring board, a flip-chip mounting method in which a semiconductor chip in which convex electrodes (bumps) made of eutectic solder, high-temperature solder, gold, or the like are formed in connection pad portions is used, and these bumps are made to face, brought into contact with, and melting/diffusion-joined to the corresponding terminal portions on a chip-mounting substrate using a so-called face down method has been employed.
The semiconductor chip that is used in this mounting method is obtained by, for example, dividing a semiconductor wafer having bumps formed on a circuit surface by grinding a surface opposite to the circuit surface or dicing. In the process of obtaining the above-described semiconductor chip, generally, for the purpose of protecting the bump-formed surface of the semiconductor wafer, a curable resin film is attached to the bump-formed surface, and this film is cured so as to form a protective film on the bump-formed surface. As the above-described curable resin film, a curable resin film containing a thermosetting component that is cured by heating is broadly used, and, as a protective film-forming sheet including the above-described thermosetting resin film, a protective film-forming sheet formed by stacking a thermoplastic resin layer having a specific thermal elastic modulus on the film and further stacking a thermoplastic resin layer which is not plastic at 25° C. on the uppermost layer of the thermoplastic resin layer has been disclosed (refer to Patent Document 1).
In addition, according to Patent Document 1, this protective film-forming sheet is excellent in terms of the bump-filling property of the protective film, the wafer workability, the electric connection reliability after resin sealing, and the like.